Horizontal subrack and communication cabinet

ABSTRACT

A horizontal subrack includes a ventilation box, a fan box and a board area. The ventilation box is located on the top and/or at the bottom of the board area, and includes an air partition plate, an air inlet, and a first air outlet; the air partition plate is set inside the ventilation box, and divides the ventilation box into an air-in chamber and an air-out chamber; the fan box is installed in the air-in chamber, and a fan is installed on the fan box; the air inlet is set on the front wall of the ventilation box; and the first air outlet is set on the rear wall of the ventilation box. The board area includes board slots, an air-in duct and an air-out duct.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/818,792, filed on Jun. 18, 2010, which is a continuation ofInternational Application No. PCT/CN 2008/073718, filed on Dec. 25,2008, which claims the priority of Chinese Patent Application No.200810007994.4, filed on Feb. 22, 2008, both of which are herebyincorporated by reference in their entireties.

TECHNICAL FIELD

The present invention relates to electronic and communication equipment,and in particular, to a horizontal subrack for holding board devices.

BACKGROUND

When horizontal subracks are configured in the electronic andcommunication equipment cabinet, horizontal subracks indifferent forms(for example, with a lengthwise air duct, or with a widthwise air duct)may exist in the same cabinet. FIG. 1 shows a horizontal subrack with alengthwise air duct in the prior art. The horizontal subrack includes aboard area 14. Boards are located in the board area 14, and a fan box 13is located on the right side of the board area 14. The fan is installedin the fan box 13. A ventilation box is set on the right side of the fanbox 13, and multiple air inlets 11 are set in the front of theventilation box. An air deflector box 15 is located on the left side ofthe board area 14, and a first air outlet 12 is set at the rear of theair deflector box 15.

When the boards in the board area 14 need to dissipate heat, theexternal airflow enters through the air inlet 11. Under the effect ofthe axial flow fan, the airflow enters the board area 14 to dissipateheat for the boards in the board area 14, and then flows out of thefirst air outlet 12 of the air deflector box on the left side of theboard area.

In the process of developing the present invention, the inventor findsat least the following defects in the prior art:

The horizontal subrack uses an axial flow fan to dissipate heat. Becausethe widthwise dimension of the horizontal subrack is limited, the axialflow fan blows the cool air onto the board directly. As affected by thefan hub, the cool air from the fan is not mixed sufficiently beforearriving at the board area. Consequently, the air volume is not even forthe board slots in the board area of the horizontal subrack, which is abottleneck of enhancing the heat dissipation capability of thehorizontal subrack.

SUMMARY

The embodiments of the present invention provide a horizontal subrackand a communication cabinet to improve the evenness of the air volume tothe slots of the horizontal subrack and overcome the bottleneck ofenhancing the heat dissipation capability of the horizontal subrack.

The horizontal subrack and the communication cabinet provided in anembodiment of the present invention are fulfilled through the followingtechnical solution.

The horizontal subrack includes a ventilation box, a fan box, and aboard area.

The ventilation box is located on the top and/or at the bottom of theboard area, and includes an air partition plate, an air inlet, and afirst air outlet.

The air partition plate is set inside the ventilation box, and dividesthe ventilation box into an air-in chamber and an air-out chamber.

The fan box is set in the air-in chamber, and a fan is installed on thefan box.

The air inlet is set on the front wall of the ventilation box, and islocated in the air-in chamber.

The first air outlet is set on the rear wall of the ventilation box, andis located in the air-out chamber.

The board area includes board slots, an air-in duct, and an air-outduct. The air-in duct is located on one side of the board slots, and theair-out duct is located on the other side of the board slots. The air-induct is linked to the air-in chamber, and the air-out duct is linked tothe air-out chamber.

Another horizontal subrack provided in an embodiment of the presentinvention includes: a ventilation box, a fan box, and a board area.

The ventilation box is located on the top and/or at the bottom of theboard area, and includes an air partition plate, an air inlet, and afirst air outlet.

The air partition plate is set inside the ventilation box, and dividesthe ventilation box into an air-in chamber and an air-out chamber.

The fan box is set on the rear wall of the board area, and a fan isinstalled on the fan box.

The air inlet is set on the front wall of the ventilation box, and islocated in the air-in chamber.

The first air outlet is set on the rear wall of the ventilation box, andis located in the air-out chamber.

The board area includes board slots, an air-in duct, and an air-outduct. The air-in duct is located on one side of the board slots, and theair-out duct is located on the other side of the board slots. The air-induct is linked to the air-in chamber, and the air-out duct is linked tothe air-out chamber.

The communication cabinet provided in an embodiment of the presentinvention includes a horizontal subrack. The horizontal subrack includesa ventilation box, a fan box, and a board area.

The ventilation box is located on the top and/or at the bottom of theboard area, and includes an air partition plate, an air inlet, and afirst air outlet.

The air partition plate is set inside the ventilation box, and dividesthe ventilation box into an air-in chamber and an air-out chamber.

The fan box is set in the air-in chamber or on the rear wall of theboard area, and a fan is installed on the fan box.

The air inlet is set on the front wall of the ventilation box, and islocated in the air-in chamber.

The first air outlet is set on the rear wall of the ventilation box, andis located in the air-out chamber.

The board area includes board slots, an air-in duct, and an air-outduct. The air-in duct is located on one side of the board slots, and theair-out duct is located on the other side of the board slots. The air-induct is linked to the air-in chamber, and the air-out duct is linked tothe air-out chamber.

Evidently, the horizontal box and the communication cabinet extend thetrail from the fan box to the board area, and significantly reduce theimpact of the airflow onto the fan hub. The cool air from the fan ismixed sufficiently before arriving at the board area, and the air volumeis allocated evenly to the board slots in the horizontal subrack.Therefore, the heat dissipation capability of the horizontal subrack isenhanced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a structure of a horizontal subrack in the prior art;

FIG. 2 shows a structure of a first type of horizontal subrack in anembodiment of the present invention;

FIG. 3 shows a structure of a second type of horizontal subrack in anembodiment of the present invention;

FIG. 4 is an exploded view of a second type of horizontal subrack in anembodiment of the present invention;

FIG. 5 shows a structure of a third type of horizontal subrack in anembodiment of the present invention; and

FIG. 6 shows a structure of a fourth type of horizontal subrack in anembodiment of the present invention.

DETAILED DESCRIPTION

The horizontal subrack provided in an embodiment of the presentinvention includes: a ventilation box, a fan box, and a board area.

The ventilation box is located on the top and/or at the bottom of theboard area, and includes an air partition plate, an air inlet, and afirst air outlet.

The air partition plate is set inside the ventilation box, and dividesthe ventilation box into an air-in chamber and an air-out chamber.

The fan box is set in the air-in chamber or on the rear wall of theboard area, and a fan is installed on the fan box.

The air inlet is set on the front wall of the ventilation box, and islocated in the air-in chamber.

The first air outlet is set on the rear wall of the ventilation box, andis located in the air-out chamber.

The board area includes board slots, an air-in duct, and an air-outduct. The air-in duct is located on one side of the board slots, and theair-out duct is located on the other side of the board slots. The air-induct is linked to the air-in chamber, and the air-out duct is linked tothe air-out chamber.

Evidently, the horizontal box extends the trail from the fan box to theboard area, and reduces the impact of the airflow onto the fan hubmassively. The cool air from the fan is mixed sufficiently beforearriving at the board area, and the air volume is allocated evenly tothe board slots in the horizontal subrack. Therefore, the heatdissipation capability of the horizontal subrack is enhanced.

The technical solution under one embodiment of the present invention isdescribed in more detail with reference to the accompanying drawings.

FIG. 2 is an exploded view of a first type of horizontal subrack in anembodiment of the present invention, and FIG. 3 shows a structure of afirst type of horizontal subrack already installed in an embodiment ofthe present invention. In FIG. 2 and FIG. 3, the top cover plate of thehorizontal subrack is removed.

The horizontal subrack includes: a ventilation box 202, a ventilationbox 203, and a board area 204. The ventilation box 202, the ventilationbox 203, and the board area 204 are independent of each other. They areinstalled together to form a complete horizontal subrack shown in FIG.3. The ventilation box 202 and the ventilation box 203 are located onthe top and at the bottom of the board area 204 respectively. In thisembodiment, the structure of the ventilation box 202 is the same as thatof the ventilation box 203. The structure of the ventilation box 202 isdescribed below.

The ventilation box 202 includes an air-in chamber 205, an air-outchamber 208, an air inlet 201, a first air outlet 210, an air partitionplate 209, a fan box 206, and a fan 207.

The air partition plate 209 is set in the ventilation box 202, anddivides the ventilation box 202 into an air-in chamber 205 and anair-out chamber 208. The air-in chamber 205 is located on one side (suchas the right side) of the air partition plate 209, and the air-outchamber 208 is located on the other side (such as the left side) of theair partition plate 209. The air-in chamber 205 is an area between theair partition plate 209 and the right sidewall 212 of the ventilationbox 202, and the air-out chamber 208 is an area between the airpartition plate 209 and the left sidewall 215 of the ventilation box202. The air inlet 201 of the air-in chamber 205 is set on the frontwall 216 of the ventilation box 202, and the first air outlet 210 of theair-out chamber 208 is set on the rear wall 217 of the ventilation box202.

The fan box 206 is located between the air partition plate 209 and theright sidewall 212 of the horizontal subrack, and divides the air-inchamber 205 into two areas, and is located above the board area 204. Afan 207 is installed on the fan box 206. There may be one or more fans207 for inhaling external cool air into the air-in chamber 205.

The central part of the horizontal subrack is a board area 204. Theboard area 204 includes board slots, an air-in duct 213, and an air-outduct 214. The air-in duct 213 is located on one side (for example, rightside) of the board slot, and the air-out duct 214 is located on theother side (for example, left side) of the board slot. The board slot isadapted to hold a board, and a gap for air ventilation exists betweenevery two board slots. The air inlet of the air-in duct 213 is linked tothe outlet of the air-in chamber 205 of the ventilation box 202. Theair-out duct 214 is linked to the first air outlet 210 of the air-outchamber 208. The rear wall of the air-out duct 214 may have a second airoutlet 218.

The cool air enters the ventilation box 202 through the air inlet 201.Under the effect of the fan 207, the cool air passes through the air-inchamber 205, the air-in duct 213, and then goes into the board slot ofthe board area 204. The cool air flows through the gaps between boardslots in the board area 204 to dissipate heat of components, and entersthe air-out chamber 208 through the air-out duct 214 before beingexpelled from the horizontal subrack through the first air outlet 210and the second air outlet 218.

In the horizontal subrack provided in this embodiment, the ventilationbox is set on the top and at the bottom of the horizontal subrack. Anair-in chamber and an air-out chamber are set in the ventilation box,and the fan box is set in the air-in chamber and located above the boardarea, thus prolonging the trail between the fan and the board slot. Thecool air is distributed evenly before entering the board area 204.Therefore, the impact on the fan hub is eliminated, which is caused byblowing air to the board area directly, and the evenness of distributingthe air volume to the slots in the horizontal subrack is improved.

In this embodiment, the ventilation box 202, the ventilation box 203,and the board area 204 are independent of each other. Therefore, theuser may select the proper ventilation box and the quantity ofventilation boxes to match the board area 204 according to the size ofthe system power consumption and the quantity of the board slots. Asshown in FIG. 5, when there are few (for example, 2 or 3) slots in thesubracks, a ventilation box may be installed on the top or at the bottomof the main body of the horizontal subrack, and a proper fan isinstalled to dissipate heat.

Alternatively, the ventilation box 202, the ventilation box 203, and theboard area 204 are set to a whole. In this way, the impact on the fanhub is eliminated, which is caused by blowing air to the board areadirectly, and the evenness of distributing the air volume to the slotsin the horizontal subrack is improved.

FIG. 4 shows a structure of a second type of horizontal subrack in anembodiment of the present invention. As shown in FIG. 4, the top coverplate is removed from the horizontal subrack. In the structure of thehorizontal subrack, the air enters the subrack from the front of thesubrack, and flows out at the rear of the subrack, and the airflow inthe board area flows from one side to the other.

The horizontal subrack includes a ventilation box 402, a ventilation box403, and a board area 404. The ventilation box 402 and the ventilationbox 403 are located on the top and at the bottom of the board area 404respectively. In this embodiment, the ventilation box 402 at the upperpart of the horizontal subrack is structurally the same as theventilation box 403 at the lower part of the horizontal subrack.Therefore, only the structure of the ventilation box 402 is describedherein.

The ventilation box 402 includes an air-in chamber 405, an air-outchamber 408, an air inlet 401, a first air outlet 410, an air partitionplate 409, a fan box 406, and a fan 407.

The air partition plate 409 for isolating the hot air from the cool airis located on the diagonal of the four edges of the ventilation box 402,and divides the ventilation box 402 into an air-in chamber 405 and anair-out chamber 408. The air-in chamber 405 is located on one side (suchas the right side) of the air partition plate 409, and is an areabetween the air partition plate 409 and the right sidewall 412 of theventilation box 402. The air-out chamber 408 is located on the otherside (such as the left side) of the air partition plate 409, and is anarea between the air partition plate 409 and the left sidewall 415 ofthe ventilation box 402. The air inlet 401 of the air-in chamber 405 isset on the front wall 416 of the ventilation box 402, and the first airoutlet 410 of the air-out chamber 408 is set on the rear wall 417 of theventilation box 402.

The central part of the horizontal subrack is a board area 404. Theboard area 404 includes board slots, an air-in duct 413, and an air-outduct 414. The air-in duct 413 is located on one side (for example, rightside) of the board slot, and the air-out duct 414 is located on theother side (for example, left side) of the board slot. The board slot isadapted to hold a board, and a gap for air ventilation exists betweenevery two board slots. The air inlet of the air-in duct 413 is linked tothe outlet of the air-in chamber 405 of the ventilation box 402. Theair-out duct 414 is linked to the first air outlet 410 of the air-outchamber 408. The rear wall of the air-out duct 414 also has a second airoutlet.

The fan box 406 is set in the air-in chamber 405, and is parallel to thefront wall 416 of the ventilation box 402, and is close to the air inlet401. One or more fans are installed on the fan box 406.

In this embodiment, a deflecting plate 411 is set in the air-in chamber405. The deflecting plate 411 partitions the fans 407 from each other onthe fan box 406, and is parallel to the air partition plate 409. Thedeflecting plate 411 divides the air-in chamber 405 into multiple areasalong the depth direction of the horizontal subrack.

The cool air enters the ventilation box 402 through the air inlet 401under the effect of the fan, passes through the air-in chamber 405, theboard area 404 and the air-in duct 413, and then arrives at the boardslots of the board area 404. The cool air is mixed sufficiently beforeentering the board area 404. The cool air flows through the gaps betweenboard slots in the board area 404 to dissipate heat of components, andenters the air-out chamber 408 through the air-out duct 414 in the boardarea 404 before being expelled from the horizontal subrack through thefirst air outlet 410 and the second air outlet.

This horizontal subrack differs from the first type of horizontalsubrack described above in that: A deflecting plate 411 is set along thedepth direction of the second type of fan box 406. The deflecting plate411 divides the air-in chamber 405 into multiple areas along the depthdirection of the air partition plate 409, thus ensuring evenness ofdistributing airflow along the depth direction of the fan box, andmaking the airflow impose less impact on the fan hub. Moreover, adeflecting plate is set inside the ventilation box (the deflecting platemay be in other shapes). Therefore, the airflow of the fan at the inletis further improved, the airflow of the fan at the outlet spreadssufficiently, turbulence is reduced, and the system pressure loss isreduced. Because each fan has its independent air-in duct,cross-interference is eliminated between fans. The working points of thefan are optimized, and the system noise is reduced efficiently.

FIG. 5 shows a third type of horizontal subrack provided in anembodiment of the present invention. Such horizontal subrack differsfrom that shown in FIG. 4 in that: The air partition plate 509 isarcual, and the deflecting plate 511 divides the air-in chamber 505 intomultiple arcual areas along the depth direction of the horizontalsubrack. The deflecting plate 511 is parallel to the air partition plate509, and is also arcual (or in other shapes). The fan box 506 is locatedbetween the right sidewall 512 of the ventilation box 502 and thedeflecting plate 511, and is parallel to the right sidewall 512. Thedeflecting plate 511 begins with the air inlet 501 and ends at the fanbox 506. The deflecting plate 511 makes the airflow that passes througheach fan form a separate channel. The horizontal subrack shown in FIG. 5may produce the technical effect of the horizontal subrack shown in FIG.4.

FIG. 6 shows a structure of a fourth type of horizontal subrack in anembodiment of the present invention. As shown in FIG. 6, the top coverplate is removed from the horizontal subrack. In the structure of thehorizontal subrack, the air enters the subrack from the front of thesubrack, and flows out at the rear of the subrack, and the airflow inthe board area flows from one side to the other.

The horizontal subrack includes a ventilation box 602, a ventilation box603, and a board area 604. The ventilation box 602 and the ventilationbox 603 are located on the top and at the bottom of the board area 604respectively. In this embodiment, the ventilation box 602 at the upperpart of the horizontal subrack is structurally the same as theventilation box 603 at the lower part of the horizontal subrack.Therefore, only the structure of the ventilation box 602 is describedherein.

The ventilation box 602 includes an air-in chamber 605, an air-outchamber 608, an air inlet 601, a first air outlet 610, an air partitionplate 609, a fan box 606, and a fan 607.

The air partition plate 609 for isolating the hot air from the cool airis located on the diagonal of the four edges of the ventilation box 602,and divides the ventilation box 602 into an air-in chamber 605 and anair-out chamber 608. The air-in chamber 605 is located on one side (suchas the right side) of the air partition plate 609, and is an areabetween the air partition plate 609 and the right sidewall 612 of theventilation box 602. The air-out chamber 608 is located on the otherside (such as the left side) of the air partition plate 609, and is anarea between the air partition plate 609 and the left sidewall 615 ofthe ventilation box 602. The air inlet 601 of the air-in chamber 605 isset on the front wall 616 of the ventilation box 602, and the first airoutlet 610 of the air-out chamber 608 is set on the rear wall 617 of theventilation box 602.

The fan box 606 is located on the rear wall of the board area, and isclose to the rear wall 617 of the board area. The fan box 606 covers thefirst air outlet 610 on the rear wall 617 of the ventilation box and therear wall of the board area 604. One or more fans 607 are installed onthe fan box 706.

The central part of the horizontal subrack is a board area 604. Theboard area 604 includes board slots, an air-in duct 613, and an air-outduct 614. The air-in duct 613 is located on one side (for example, theright side) of the board slot, and the air-out duct is located on theother side (for example, the left side) of the board slot. The boardslot is adapted to hold a board, and a gap for air ventilation existsbetween every two board slots. The air inlet of the air-in duct 613 islinked to the outlet of the air-in chamber 605 of the ventilation box602. The air-out duct 614 is linked to the first air outlet 610 of theair-out chamber 608. The rear wall of the air-out duct 614 may have asecond air outlet.

The cool air enters the ventilation box 602 through the air inlet 601.Under the effect of the fan 607, the cool air passes through the air-inchamber 605 and the air-in duct 613 and arrives at the board slots inthe board area 604, thus prolonging the trail between the fan and theboard. The cool air is mixed sufficiently, thus eliminating the impacton the fan hub, which is caused by the direct air blown by the fan tothe board area 604, and improving the evenness of the air volumedistributed to the board slots. The mixed cool air flows through theboard area 604 to dissipate heat for the components, and passes throughthe air-out duct 614 and the air-out chamber 608 before being expelledfrom the horizontal subrack through the first air outlet 610 and thesecond air outlet.

In this embodiment, the fan box is located at the rear of the horizontalsubrack, and covers the first outlet, the second outlet, and the rearwall of the board area, thus facilitating installation of large-sizefans without the need of increasing the height of the horizontalsubrack.

Further, the fan box 606 may be set in front of the ventilation box 602to accomplish the objectives of the present invention.

In the embodiments described above, different ventilation boxes may beinstalled on the top and at the bottom of the board area separately; or,if the board area is small, the ventilation boxes may be installed onlyon the top or only at the bottom of the board area, with a view todissipating heat for the board components.

A communication cabinet provided in an embodiment of the presentinvention includes a horizontal subrack. The horizontal subrack includesa ventilation box, a fan box, and a board area.

The ventilation box is located on the top and/or at the bottom of theboard area, and includes an air partition plate, an air inlet, and afirst air outlet.

The air partition plate is set inside the ventilation box, and dividesthe ventilation box into an air-in chamber and an air-out chamber.

The fan box is set in the air-in chamber or on the rear wall of theboard area, and a fan is installed on the fan box.

The air inlet is set on the front wall of the ventilation box, and islocated in the air-in chamber.

The first air outlet is set on the rear wall of the ventilation box, andis located in the air-out chamber.

The board area includes board slots, an air-in duct, and an air-outduct. The air-in duct is located on one side of the board area, and theair-out duct is located on the other side of the board area. The air-induct is linked to the air-in chamber, and the air-out duct is linked tothe air-out chamber.

Further, a second air outlet is set on the rear wall of the air-outduct, and the airflow of the board area passes through the air-outchamber and the air-out duct before being expelled from the first airoutlet and the second air outlet.

Further still, the fan box is set in the air-in chamber in this way: Thefan box is installed inside the air-in chamber and located between theair partition plate and the right sidewall of the ventilation box.

Further still, the fan box is set in the air-in chamber in this way: Thefan box is installed inside the air-in chamber and is close to the frontwall of the ventilation box.

Further still, a deflecting plate is set in the depth direction of theair partition plate in the air-in chamber of the ventilation box. Thedeflecting plate isolates one fan from another, and divides the air-inchamber into a certain number of areas, where the number is equal to thenumber of fans.

Further still, the deflecting plate is an arcual plate or a straightplate.

Further still, the deflecting plate is parallel to the air partitionplate.

Elaborated above are a horizontal subrack and a communication cabinetunder the present invention. Although the invention is described throughsome exemplary embodiments, the invention is not limited to suchembodiments. It is apparent that those skilled in the art can makemodifications and variations to the invention without departing from thescope of the invention. The invention is intended to cover suchmodifications and variations provided that they fall in the scope ofprotection defined by the following claims or their equivalents.

What is claimed is:
 1. A horizontal subrack comprising at least oneventilation box, a fan box, and a board area, wherein the at least oneventilation box is located on the top or at the bottom of the boardarea, and includes an air partition plate, an air inlet, and a first airoutlet; the air partition plate is set inside the ventilation box, anddivides the ventilation box into an air-in chamber and an air-outchamber; the fan box is set in the air-in chamber, and a fan isinstalled on the fan box; the air inlet is set on the front wall of theventilation box, and is located in the air-in chamber; the first airoutlet is set on the rear wall of the ventilation box, and is located inthe air-out chamber; the board area comprises board slots, an air-induct, and an air-out duct, the air-in duct is located on one side of theboard slots, the air-out duct is located on the other side of the boardslots, the air-in duct is linked to the air-in chamber, and the air-outduct is linked to the air-out chamber.
 2. The horizontal subrackaccording to claim 1, wherein the fan box is set in the air-in chamberin this way: the fan box is installed inside the air-in chamber and isclose to the front wall of the ventilation box.
 3. The horizontalsubrack according to claim 1, wherein a deflecting plate is set in thedepth direction of the air partition plate in the air-in chamber of theventilation box, the deflecting plate isolates one fan from another anddivides the air-in chamber into a certain number of areas, where thenumber is equal to the number of fans.
 4. The horizontal subrackaccording to claim 3, wherein the deflecting plate is a straight plate.5. A communication cabinet comprising a horizontal subrack, and thehorizontal subrack comprises at least one ventilation box, a fan box,and a board area, wherein the at least one ventilation box is located onthe top or at the bottom of the board area, and comprises an airpartition plate, an air inlet, and a first air outlet; the air partitionplate is set inside the ventilation box, and divides the ventilation boxinto an air-in chamber and an air-out chamber; the fan box is set in theair-in chamber, and a fan is installed on the fan box; the air inlet isset on the front wall of the ventilation box, and is located in theair-in chamber; the first air outlet is set on the rear wall of theventilation box, and is located in the air-out chamber; the board areacomprises board slots, an air-in duct, and an air-out duct, the air-induct is located on one side of the board slots, the air-out duct islocated on the other side of the board slots, the air-in duct is linkedto the air-in chamber, and the air-out duct is linked to the air-outchamber.
 6. The communication cabinet according to claim 5, wherein asecond air outlet is set on the rear wall of the air-out duct, and theairflow of the board slots passes through the air-out chamber and theair-out duct before being expelled from the first air outlet and thesecond air outlet.
 7. The communication cabinet according to claim 5,wherein the fan box is set in the air-in chamber in this way: the fanbox is installed inside the air-in chamber and is close to the frontwall of the ventilation box.
 8. The communication cabinet according toclaim 7, wherein a deflecting plate is set in the depth direction of theair partition plate in the air-in chamber of the ventilation box, thedeflecting plate isolates one fan from another and divides the air-inchamber into a certain number of areas, where the number is equal to thenumber of fans.